| 结合实测光谱的ASTER TIR数据岩性划分与构造样式分析:以新疆阿克苏蓝片岩为例 |
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| 引用本文： | 张志,管志超,王少军.结合实测光谱的ASTER TIR数据岩性划分与构造样式分析:以新疆阿克苏蓝片岩为例[J].吉林大学学报(地球科学版),2018(1):334-342. |
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| 作者姓名： | 张志 管志超 王少军 |
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| 作者单位： | 中国地质大学(武汉)地球物理与空间信息学院,武汉,430074
武汉大学测绘遥感信息工程国家重点实验室,武汉,430079
中国地质大学(武汉)公共管理学院,武汉,430074 |
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| 基金项目： | 中国地质调查局项目(DD20160068)Supported by Project of China Geological Survey (DD20160068) |
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| 摘 要： | 常见造岩矿物的特征谱带位于热红外区域,因此热红外遥感在岩石地层划分与构造样式分析方面有巨大的应用潜力,并且精细岩石地层划分是构造样式分析的基础。新疆阿克苏蓝片岩被认为是目前世界范围内保存最好的前寒武纪蓝片岩之一。本文对该地质体中采集的不同类型岩石样品进行了室内热红外发射光谱测试,发现白云母石英片岩类残余辐射特征(restrahlen features,RF)位于波长8.55、9.16和9.60μm处,绿泥绿帘片岩类RF位于波长9.60、10.50和11.66μm处。按照ASTER TIR波段位置将样品的发射率光谱曲线重采样,利用ASTER TIR数据计算基性指数I_b和白云母指数I_m。依据I_b和I_m得到不同岩性段分布图,该图能反映蓝片岩地质体中不同基性程度岩石、后期侵入的基性岩墙群以及白云母石英片岩单元的空间分布。从岩性区域分布特征看,我们认为新疆阿克苏蓝片岩地质体平面构造样式表现为褶皱,其轴迹线为NE—SW向,这一结果与前人对其划分的单斜地层结构有较大的差异。另外,褶皱出现在地质体南部,说明其北部所受压力较南部小,与前人认识一致。研究结果体现了热红外遥感结合实测光谱可有效探测矿物岩石信息的优势,该方法可为相关研究提供参考。
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| 关 键 词： | 实测光谱 ASTER TIR 矿物指数 岩性划分 褶皱 蓝片岩 measured spectra ASTER TIR mineral index lithological classification fold blueschist |
A Method of Combining Measured Spectra and ASTER TIR Image to Divide Lithology for New Tectonic Style Analysis: Based on the Blueschist in Akesu |
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| Zhang Zhi,Guan Zhichao,Wang Shaojun.A Method of Combining Measured Spectra and ASTER TIR Image to Divide Lithology for New Tectonic Style Analysis: Based on the Blueschist in Akesu[J].Journal of Jilin Unviersity:Earth Science Edition,2018(1):334-342. |
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| Authors: | Zhang Zhi Guan Zhichao Wang Shaojun |
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| Abstract: | The research tries to solve the problem of lithological classification in the area where it's hard to implement a geological survey,in the meanwhile,by using a thermal method to find tectonic features which are hidden under the visible light.Some minerals,like quartz and feldspar,do not exhibit absorption features in the VNIR and SWIR regions,but display fundamental molecular absorption features in the TIR wavelength region.These characteristic spectra always reserve on the rock surface's measured spectra.On the basis of the emissivity spectra of the rock samples which are measured by FTIR in the region of thermal infrared spectroscopy,the lithology could be classified by band ratio method of ASTER TIR image.The measured emissive spectra of blueschist rock samples' in Akesu carry a large amount of information.The Restrahlen Features (RF) positions of muscovite quartz schist are similar to that of the monzonitic quartz schist.Their resampled spectra curve shows that the rock emissivity increases from ASTER Band 12 to Band 13,but only muscovite quartz schist has a higher emissivity value in Band 13 and Band 14 than Band 10 and Band 12,which could be distinguished from other samples.The Muscovite Index (I m =((B 14 · B 13) / (B 10 · B 12)) is established to indicate the distribution of muscovite's content in the study area.The chlorite epidote schist's spectra are in the high value position,which is the same as that of the rock diabase,but it still has a significant RF position in wavelength 10.5μm corresponding to the ASTER Band 13.So we built up the Basite Index (Ib=(B12 · B14)/ (B13 · B13) to indicate the basic rocks in Akesu geological body.According to these two expressions,we obtained band ratios on ASTER TIR emissivity products,and got the results of Akesu thermal infrared Im and Ib image in a colored lookup table.Ib and Im images have a good reflection of the lithology distribution,which indicates a rich content of muscovite in the southeast Akesu and a rich basic rock in the northeast Akesu.The stratum in the northwest could be devided into several layers corresponding to the samples we collected in the field work.The diabases are clearly visible in Ib image.On the basis of these images,we drew a new Geological sketch map and found a rootless hook fold in Akesu blueschist.The previous research did not exhibit it on their map.The rootless hook fold indicates that the south part of Akesu bluesehist bore a greater pressure than the north part.It illustrates a tectonic model of oceanic plate southward subduction to Tarim craton which has been put forward by Nakajima in 1990,and the thesis of Wentao Huang has a same conclusion as ours.The authors consider that thermal infrared remote sensing has a wide application prospection for mineral identification and lithological classification. |
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